What I''m going to say isn''t 100% accurate, (so I can explain it easier and for you to understand easier) but I hope you get the idea behind it.

Under modern operating systems, the OS will allocate a certain section of memory for the program to use... Since you can multi-task (run more than 1 program at once), the OS has to make sure the programs don''t step outside their allocated memory so they don''t read info from other programs currently running or write to other programs memory section to screw them up.

So, the message you are seeing is basically the Operating system crashing the programming that is reading memory outside its allocated section. This is usually due to a coding issue (a bug in code --- the games should have patches to fix this type of thing but sometimes they aren''t available)

Likewise you can also get "can''t be written." which is writing memory outside their allocated memory space...